1. Field of the Invention
This invention relates generally to rolling mills producing hot rolled rods, bars and other like bendable elongated products, and is concerned in particular with an improved apparatus for guiding such products as they move longitudinally at high speeds along curved paths.
2. Description of the Prior Art
In a typical modern day rod mill, delivery speeds range from about 5 to 150 m/sec, with rod diameters ranging from about 5.0 to 22.4 mm. As the hot rolled product exits from the mill, it is directed longitudinally along a horizontal path leading through a succession of water boxes before being guided downwardly by a "turndown" apparatus into an inclined laying head. The laying head forms the rod into a succession of rings which are received in an overlapping offset pattern on a conveyor. While on the conveyor, the rings are subjected to various thermal treatments before finally being delivered to a reforming chamber in which they are gathered into large coils.
Conventional turndowns typically employ pairs of guide rollers between which the product is guided along a downwardly curved path leading to the laying head. The spacing between the guide rollers is not adjustable to accommodate different product diameters. Thus, when the rolling schedule calls for a change in product size, for example from 5 to 10 mm., the mill must be shut down so that the guide rollers of the turndown can be changed to a different diameter selected to accommodate the next product size. Alternatively, the turndown can be provided with multiple pairs of different diameter guide rollers coaxially mounted on the same support shafts. In such cases, the entire turndown must be shifted in the direction of the roller axes so as to align differently sized roller pairs with the guide path.
Considerable costs are involved in maintaining the required inventory of different diameter guide rollers. Moreover, valuable production time is lost when changing from one guide roller size to another in order to accommodate different product sizes.
The objective of the present invention is to eliminate the above noted problems by providing an improved turndown apparatus which is capable of handing a wide range of product sizes with the same size guide rollers.
A companion objective of the present invention is the provision of a turndown apparatus which is readily adjustable to accommodate different product sizes, thereby minimizing lost production time with a concomitant improvement in mill efficiency.